Department of Nutrition and Dietetics, Doisy College of Health Sciences of Saint Louis University, St. Louis, Missouri, USA.

Abstract

OBJECTIVE:

The role of metabolic condition and diet in regulating circulating levels of adropin, a peptide hormone linked to cardiometabolic control, is not well understood. In this study, weight loss and diet effects on plasma adropin concentrations were examined.

METHODS:

This report includes data from (1) a weight loss trial, (2) an evaluation of acute exercise effects on mixed-meal (60% kcal from carbohydrates) tolerance test responses, and (3) a meta-analysis to determine normal fasting adropin concentrations.

RESULTS:

Distribution of plasma adropin concentrations exhibited positive skew and kurtosis. The effect of weight loss on plasma adropin concentrations was dependent on baseline plasma adropin concentrations, with an inverse association between baseline and a decline in concentrations after weight loss (Spearman's ρ = -0.575; P < 0.001). When ranked by baseline plasma adropin concentrations, only values in the upper quartile declined with weight loss. Plasma adropin concentrations under the main area of the bell curve correlated negatively with habitual carbohydrate intake and plasma lipids. There was a negative correlation between baseline values and a transient decline in plasma adropin during the mixed-meal tolerance test.

CONCLUSIONS:

Plasma adropin concentrations in humans are sensitive to dietary macronutrients, perhaps due to habitual consumption of carbohydrate-rich diets suppressing circulating levels. Very high adropin levels may indicate cardiometabolic conditions sensitive to weight loss.

The macronutrient intake data (in kJ per person, or expressed relative to other macronutrients) and plasma adropin concentration data were converted into z-scores (±SD from the mean) to allow plotting total and relative intake data on the same graph. White circles = total intake; grey circles = intake relative to other macronutrients; n=62(A–C) Scatterplots showing a nonlinear association between plasma adropin concentration (x-axis) and carbohydrate intake (y-axis) (A); no associations were evident for fats (B) or protein (C).(D) Carbohydrate intake of the 58 participants whose plasma adropin concentrations were within 2 SD of the mean separated into tertiles with low-normal (1st tertile, n=19), normal (2nd tertile, n=20) or highnormal (3rd tertile, n=19) plasma adropin concentrations. Carbohydrate intake (in total or relative to other macronutrients) in the 1st and 3rd tertiles was significantly different (* P<0.01). The means of the 4 participants whose plasma adropin concentrations were >2SD from the mean (“outliers”) are also shown.(E–F) Intake of fats (E) and protein (F) by tertile.

Actual values for the two arms of the study (A, C, E) and least square means of the overall meal effect (B, D, F) are shown. A and B show actual plasma adropin values, while C and D show the change in plasma adropin concentrations relative to baseline (Δadropin). A positive association between the area under the curve (AUC) for plasma adropin concentrations following the meal and baseline values is shown in E and F. White circles = post-exercise; Black circles = preexercise; grey circles = averaged meal effect.